Understanding the structure and properties of geological formations can reduce the cost of drilling wells for oil and gas exploration. Measurements made in a borehole (i.e., downhole measurements) are typically performed to attain this understanding, to identify the composition and distribution of material that surrounds the measurement device downhole.
For example, portions of the formation or cement surrounding a borehole may be imaged using various forms of energy, such as ultrasound, radio-frequency, or X-rays. Various devices may be used to obtain such images, with varying degrees of success.